Thursday, December 04, 2008

The largest saltwater crocodile in the world

[Updated July 2012]
When this story was written back in 2008, Cassius was indeed the largest saltwater crocodile in the world that we knew of. But in November 2011 we measured a much larger one called Lolong, and in June 2012 he was officially declared by Guinness to be the largest crocodile in captivity. The full story is in my 23 June 2012 blog post which is here.

[Original post]
How many times I have been asked this question: which is the largest crocodile in the world? Of course I always say that it's a saltwater crocodile (Crocodylus porosus) because the evidence we have supports that. But there's not always a lot of actual evidence of large crocodile sizes, just plenty of "big croc" stories. Still, the biggest crocodile ever measured (with a tape measure) was around 6.3 metres long (20.7 feet) from Papua New Guinea.

But what about the largest living crocodile? There may be several huge crocs living in the wild that we don't know about, but the largest living crocodile in captivity has been living on Green Island near Cairns for over 20 years. His caretaker is George Craig, a former crocodile hunter who now runs Marineland Melanesia, a shrine dedicated to crocodiles on the island. It is quite a remarkable place, which is entirely reflective of how remarkable George himself is. You see, George loves crocodiles with the kind of passion that you rarely encounter. He respects them enormously. This is why we were very keen to meet and talk with him on a recent trip to Cairns. The truth is we could have talked for weeks about crocodiles, but we only had a few hours. George was very keen to show us his pride and joy, the largest living saltwater crocodile in captivity. His name is Cassius, and he originally came from the Northern Territory. At the time he was a little under 18 feet (5.5 metres) long, but he's now around 18.5 feet (5.6 metres). Like many extremely large crocodiles, Cassius is as gentle as a lamb around his keeper, unless some food is dangled in front of him. Then, looking remarkably like a dinosaur from a forgotten age, he explodes into action and grabs the food from George. The word "grab" doesn't really do it justice, as the item of food often explodes under the pressure of those jaws. It's a remarkable and sobering sight, and if you ever need reminding how awesome crocodiles really are then a trip to Green Island to see Cassius is essential. Don't forget to talk to George Craig - rarely will you find anyone who knows more about crocodiles and understands them like he does.

Of course, you can't make such a statement without saying which ones those are, Tom! The largest croc in the US I know about falls almost two feet short of Cassius (in terms of the actual measurement, not what the sign says).

Well Adam are we supposed to believe you because you went and saw the croc. Gomek was measured at his death and was almost 18 feet long and I as a novice can tell that Utan and the other one in Miami were longer then Gomek. Next time you get a chance go see these two and make your own conclusion.

Hi Ted. Gomek was 17 feet 9 inches long. Cassius was slightly smaller than this when he was captured in 1987, but has continued to grow and was confirmed to exceed 18 feet in length at Green Island. We didn't measure Cassius during our visit, George Craig believes he is "at least 18.5 feet long" but without an actual measurement that can't be confirmed. However, the other two crocodiles you are referring to in Florida are both hybrids - C. porosus crossed with C. siamensis. So for a start they don't count (as we're talking about saltwater crocs here) and secondly I'm aware of their true sizes and they don't measure up to Gomek never mind Cassius.

There isn't another saltwater crocodile in captivity larger than 18 feet that I'm aware of, although I'd love to hear of one that was. I'd need to see some evidence too, because I know quite a few claims out there that aren't true. Although we can't confirm the current size of Cassius he has previously been confirmed as larger than any other saltie living in captivity.

I'll have you know you and Steve Irwin are an inspiration for my son, who LOVES crocs. He's only 12 but has taught his old man a thing or two about conservation.

Interesting, as am reliable conservative of a chap and never pondered some of these issues before.

Anyhow, there is a supposed "largest" croc named Utan who used to be kept at Alligator Adventure, a touristy kind of place at Myrtle Beach, SC, USA.

Not sure if you're familiar.

He's one big booger. I'll say that. If seen films of this monster eating from people's hands, (but not the keepers),so I guess there goes the whole thing about arguments of nature vs. nurture--though I'd say he's probably not trustworthy with children.

Any more input on this Utan guy, supposedly at 17 plus feet?

Hard to fathom Utan is even indirectly related to the little caiman nippers. But yeah, they all tend to look alike!

(I own a caiman crocodylus/yacare hybird presently. She's small but then I guess that's why she feels she needs to try and have a go at me)

Thought that she'd stay small. More fool me--seems that as with Utan, hybrid robustness could kick in.

Bhitarkanika on the East coast of India has been home to some of the the largest crocs (not in captivity)It has found mention in the Guinness book.There are two verifiable claims.There is a skeleton measuring 19ft 8 ins.There is a skull of a croc killed in 1926. Experts are of the opinion that the croc must have been about 25 ft.

Wakefield - Gustave is reported to be a very large Nile crocodile, but without measurements it's impossible to be accurate. Apparently he is still out there.

Rajeev - The Bhitarkanika crocodile (C. porosus) is indeed in Guinness but apparently he was sighted but never captured nor measured with a tape measure. I've tried to verify this, and it seems he was not measured. This is not the first time Guinness have included an unverified crocodile measurement in there, but perhaps it wouldn't seem so remarkable otherwise. I would love to hear otherwise from the Bhitarkanika rangers though. I'm not sure which skeleton you mean - where is that located? As for the skull, the one you're talking about (from Kanika, right?) was recently measured and, while clearly from a big croc, is too small to have come from a 23 foot crocodile based on the typical head:body ratio. Skull shape and size does vary a lot with bigger crocs, but that one is a little too far from the norm so I'm a little sceptical. However, it's clear we have a lot more to learn about giant crocs.

The 28 footer reportedly shot by Kris Pawloski relies on the word of the Pawloskis. I have great trouble with this one for several reasons. First, 28 feet is so far outside the "normal distribution" for saltwater crocodile sizes that it would be the equivalent of a 10 foot tall human in terms of believability. Secondly, I have difficulty believing that two crocodile hunters as experienced as the Pawloski's would have made two big mistakes: first, not bringing back the tiniest bit of evidence from the kill, and secondly not securing the crocodile properly so that it was still there when they returned with help.

Of course, without proof either way it could have been accurate, but knowing the vast majority of big fish stories when it comes to crocs I need more than just a story, especially for something so obviously excessive.

Great story on Cassius. I have been to see him 3 times now! And I've spoken to George on my first visit. Top bloke indeed! He really has some awesome Salties at his place. I would like to be a Crocodile expert one day and help conserve them. Can I ask, with large crocs like Gomek, Cassius, why do they look black? Compared to lesser sized ones which have a different variety of skin colour. Is it because the bigger the croc, the black colour helps them to absorb the suns engergy quicker?

dlal, George is awesome. Cassius is pretty great as well, especially up close. As to why big crocs are black, I think you've at least partly answered your own question. Crocs do change colour a fair bit, even over the course of several minutes, and they certainly get darker when they're cool and need to warm up - for exactly the reason you mentioned. It makes sense that larger crocodiles might benefit from being darker for this reason, although conversely they also benefit from "thermal intertia" - they are large enough that it also takes a long time to cool down, and so on a daily basis they actually maintain a fairly stable body temperature more independent of their behaviour. Quite how much they benefit from thermal inertia isn't known because nobody, as far as I'm aware, has measuring temperate change in such a big crocodile.

There are other reasons for colour change as well, such as mood, stress, even the colour of the environment they're in. It's often said you can tell when a saltie living in shaded freshwater creeks moves into tidal saltwater rivers because it's so much blacker as a result of adapting its body colour to its surroundings. This is one of those "I had no idea that crocs did that" facts that's fascinating.

Again, claims that the crocodile was 22 feet. Similar to the croc that was killed in PNG 2 years ago which they claimed was 7 metres long. And more recently the 28 foot croc that killed a 12 yr old girl in the Philipines.

The problem with such estimatations (and that's exactly how the article in questions detailed the size, as no one yet has tape-measured the animal) is that they are notoriously unreliable. No doubt the eye witness acounts are about as emotionally reliable as any of whose who go through such traumatic episodes.

The croc might as well be listed as 35 feet for all that matters.

I once saw a documentary where Dr. Britton and some others like Rom Whitaker tried to establish a more scientific way of determining size by studying the photos of large crocs and using a numeric formula based on average proportions of average crocs, etc, to determine length. I forget the name of the episode. Maybe Dr. Britton can fill in the details as that was some time ago.

I did not see the end of the documentary so I was not able to see if they came to any conclusions about which croc out there has the biggest rep.

In any case, it was fascinating.

I still think the largest maneater might be a non-saltie: A virtual dino named Gustave. (He's a Nile croc). Often estimated to be at or near between 18-20 feet, and possibly 60-80 years of age. Almost certainly he's all of 6 meters.

Apparently a clever lad of a croc, this guy actually stalks humans more so than being an opportunistic eater, and the problem is that anyone whose been close to him has generally never been left around to tell much about his length.

I'm a great shark/croc enthusiast from the Netherlands, and I'm currently investigating the lenght of these magnificent animals.

During my search on the web I found two big crocodiles in captivity: Yai and Utan. Both are listed at 20 feet in lenght, and it seems the lenght of Yai is verified. I've seen both pictures and video's of these specimens, and in my opinion Utan seems larger.

You've mentioned in this blog that you're aware of the true size of Utan. I'm wondering what you meant with that respond? You don't think he's 20 feet in lenght?

I'm also curious about what you know about the size of the very large salty skeleton at the Palawan Crocodile farm in the Philippines. This specimen was apparently 6 meters in lenght.

Hi Vancatu, there is one big problem with both Utan and Yai. They are not saltwater crocodiles. They are both hydrids: F1 progeny of a saltwater x siamese cross.

There's no doubt that Yai is larger than Cassius, but I'm interested in the largest saltwater crocodile in the world and consider Yai to be a bit of a cheat due to hybrid vigor. Utan is also a hybrid from the same crocodile farm, although I've been told by more than one person "in the know" that he's not as large as advertised (not even Cassius-large).

Of course I know about Gustave, in fact, he's one of the reasons I'm so interested in big crocs. I've watched his video multiple times, and calculated his length. When you see him lying next to the hippo's, you see only half of it's body. A Hippopotamus is over 3 meters long on average, so that makes Gustave almost certainly 6 meters long.

For as far as I know, the largest 'officially' recognized Nile crocodile was caught in the 1950s and measured 5.94 in length. There are also non-verified big fish stories of larger Nile Crocs, like one who was caught in 1905 and measured 6.6 meters. But where's the proof? So there's a good change that Gustave is probably the largest Nile Croc ever documented.

Dr. Britton:

It’s interesting to know that Utan probably isn't the size he's advertised. He seems larger then Yai. It's funny how video's and pictures can be so illusive. But Yai is indeed kind of a cheat, and off the record: also a very ugly crocodile.

And btw, there are also two other big Salty's in captivity in the Philippines: "Lapu-Lapu" and "Pangil". Do you also know what their real sizes are?

As time goes on, and if conservation holds firm, we might very well see the tipping of all kinds of records and scales for many species of crocs.

Of course the info I had on Gustave was likely someone's "guestimation" about ultimate sizes.

He's noteworthy for his penchant for going after humans more so than his size.

But whatever the case, he IS a big guy. I'm supposing this is the reason for some researchers wanting a closer look at him and to have a live capture, to find out the behaviors and physical traits that have apparently set him apart to even reach this age and size in the first place.

Hi Dr. Britton! First and foremost, I am a VERY big fan of yours and am very fond of your articles and documentaries concerning crocs. In regards to the world's largest croc,I have recently read an article posted some time back in 2008 by Rom Whitaker concerning the ratios between croc skull length and body length. He mentioned that the "traditional" skull to body length ratio was 1:7, with the skull measured from from the tip of the nose to the back of the occipital platform. This surprised me as from what I know, the 1:7 ratio is the ratio between the body length and the length of the skull measured from the tip of the nose to the HINGE JOINT OF THE UPPER SKULL (quadrate I think is what you call that)not the occipital platform! As for the ratio from nose to occipital platform, the ratio that I know of is 1:8. Dr. Brady Barr even confirmed this 1:8 ratio by measuring a Nile crocodile and later using this information to seek out and capture an 18 footer. But then again, this 1:8 ratio applies only to Niles not salties.

Also, I originally thought that the Kanika skull was around 40 inches long from the nose to the hinge joint, but later realized it was much smaller. On the saltwater crocodile vs great white shark episode of Animal Face-Off, it was mentioned that the robo-croc had a 40 inch skull based on the largest skull in record. If it is not the Kanika skull that was used as a mold, then what was (if there even is a skull that big)? Possibly the Paris Museum specimen?

All these facts about crocodile skulls is well...boring a hole through mine. I would really appreciate if you would help me out.

P.S.I made a saltie skull replica,that took me a year to finish. It was around 40 inches long (not including the mandible)and was based on this information. Finding out that I had been chasing a "big fish" story really made me realize even more how annoying they can be. I share your burden Dr.Britton. ;)

Hi Jason,Thanks for the comments and sorry for the long delay replying. The measurement Rom used is the standard in published literature: anterior tip of premaxilla to midpoint of the posterior margin of the cranial platform. This has generally always been used for research purposes because it’s easy to measure on an intact animal, whereas trying to find the quadrate hinge on a crocodile covered in skin and muscle is bound to be inaccurate. Skulls, on the other hand, are often measured to that point because it’s the most obvious “total length” but it leads to considerable confusion and over-estimation of total length compared with the standard nose-cranial length.

1:7 is certainly correct for C. porosus (it does vary slightly esp. in larger animals) but as Rom points out the ratio differs between species because the proportion of head length to body length can be very different. C. niloticus has a shorter head relative to body length compared with C. porosus, and Brady’s correct that it’s closer to 1:8. Gharials, on the other hand, are closer to 1:6.

The Animal Face-Off skull that was used in that episode was actually a smaller cast that was scaled up to fit the bill. It wasn’t a particularly remarkable skull, almost certainly a full or long-term captive given its terrible dentition. It was sufficient for the purposes of the show, but don’t read too much into it. We ended up using it to illustrate known facts, rather than testing bite force (which would have been pointless).

dlal, Errol is 4.7 metres long (nearly 15.5 feet). So yes, he's a big boy! Apparently he's doing great at Fort Worth Zoo, they're working him a bit harder than he's used to. To be honest his 650 kg weight is fairly high for a croc of his size, a wild croc of similar size would generally be under 600 kg.

Dr. Adam and WakefieldIn response to your (Wakefield) post dated March 13, 2009 regarding exaggeration of size of the salt water croc that attacked the poor girl check the link below to verify what the fox news said and estimation of some locals in the area regarding the size of the monstrous croc.http://newsinfo.inquirer.net/53601/giant-croc-captured-in-agusan-sur-creek.

well try to search the croc that was caught here in the philippines, it is a salt water crocodile and said that it might be the largest crocodile caught alive about 21 ft in length.. the villagers saw the crocodile eating a water buffalo..how about that?

Hi Angelo, well this is a new report since this blog post was written so it may turn out to be quite a bit bigger than Cassius. However, the first thing is to get some independent verification of its size, because I have a habit of not believing what I see in media releases. It certainly looks big enough from the photographs, but it's hard to certain without solid proof. I know this is being sought, so let's see.

Haha all I can say is the NT News must be fuming they don't have the biggest croc in the world story to report on. Haha not territory related..so no tourism attraction. Hmm I think I will go to the Phillipines for my next holiday!

Hi dlal, I don’t know about NT vs FNQ regarding the baddest and biggest croc, but well I guess both of them were amaze that they don’t have the biggest croc and I think both of them are scratching their heads too (sorry guys hahahaha).. well hope to see you in my home country.

Hello wazzup everyone. I'm a Filipino and an avid fan of the NatGeo Channel and I love watching wildlife documentaries, including crocs. I've watched videos about the biggest crocs either in captivity or in the wild in different countries in the world, which includes Cassius, the title holder. But I have never imagined that one day the Philippines will be in the headlines around the world for catching the said largest crocodile ever caught (although not yet confirmed) here in our country. I know that there are some species of crocodiles living here in the Philippines. But I never thought that a crocodile here would grow this big, which can be compared to the giant crocs that I have watched in Nat Geo. Well, I'm just amazed with such fact. And we must be very thankful that Lolong wasn't killed during the hunt. Like what Angelo said, see you in our home country. ^_^

Latest reports state that around September 27 a team of Guinness and National Geographic will visit the crocodile to verify its length.

Having seen all the pictures I could find from all different angles plus a bunch of videos, I'm pretty sure the crocodile is indeed about 6 metres, although I'm sceptical if he really is 6.4 metres. I think the 21 feet number is misinterpreted (intentional or accidental) as the original reports stated the croc was "20.1" feet, which I think is about right.

In one of the videos I saw it looked like the croc was being properly measured. Whether it will indeed turn out to be a 20 footer we'll probably know within a few weeks.

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